Going outside vs. ICW isnt going to make much difference in travel distance.
The ICW between C.Canaveral and Fernandina is essentially a 'straight shot'. It takes extra time and distance to in/out the inlets: Canaveral, St. Augustine, St.Marys, and St. Simons.
Id figure 2.5 days. If ICW then Titusville to anchor at Rockhouse Cr. @ near Ponce Inlet, leave at first light and pick up a mooring in Fernandina, again first light and Up behind Cumberland Is. / Jekyll Is. Only problem will be behind Jekyll on a low tide ... just plan well and ride the high tide wave and use your eyeballs and depthsounder instead of a chartplotter when you pass the bridge across to Jekyll ... the channnel wanders and even the daymarks arent correct vs. the actual channel.
With any wind from the south quarter, just SAIL / motor sail from Titusville to New Smyrna, and again from New Smyrna on up to Fernandina, etc.
If the weather is good, go outside from Fernandina and enter the St. Simons Bay to save the wandering/shallow water behind Jekyll. Best weather advice for this area is Caribbean Weather (Chris Parker) on SSB 4.045 mHz USB starting a 730AM ... just listen to all the private forecasts being made, especially for along the FL/GA coast.
When/IF passing through Volusia County (Daytona & New Smyrna) ... BE SURE your holding tank overboard seacock is LOCKED with tie wrap, etc. ... or 'ticket', sometimes with 'guns drawn'.
Since this is a straight shot trip, it makes no difference in distance travelled if inside or outside ... and you can anchor or take a mooring along the ICW. 3 10-12+ hour days on the ICW or 30+ hours if 'outside'.
YOur route is too close to the coast for any help from the Gulf Stream:
http://passageweather.com/index.htm?http://passageweather.com/northatlantic.htm ---> click on Gulf stream in the 'title bar' of the 'weather chart'.